A constitution for driving a motor with a high efficiency using a fuel cell as the main power source is disclosed as prior art in Publication of Unexamined Japanese Patent Application No. 2002-118981. Electrical power supply systems may include a battery and a fuel cell connected in parallel to supply power, e.g., to an electric motor. The fuel cell may be operable to charge the battery. Such systems may also include a DC-DC converter, to control the power ratio between the battery and the fuel cell.
In systems which provide DC/DC converters, energy losses are generated in the semiconductor switching and coils of DC/DC converters.